Study protocol for a randomized controlled trial investigating the effect of online interpretation bias intervention on stress reactivity in the children of parents with depression: the CoCo study.

BACKGROUND: Current preventive interventions for the children of parents with depression demonstrate modest effects on depression incidence. This may be because existing interventions tend to comprise general psychotherapeutic tools, rather than targeting the specific mechanisms underlying familial transmission. Improved theoretical models of familial transmission could enhance the development of targeted interventions. Although existing models assume that cognitive and biological vulnerability factors influence one another, the precise mechanisms are unknown. This project is the first to experimentally test whether negative interpretation bias has an impact on cortisol response in children of parents with depression. This study protocol reports a randomised controlled trial of an interpretation bias intervention which aims to shift participants' interpretation bias in a more positive direction and thereby alter their stress response. METHODS: Children aged 10-14 years who have i) one parent with a current or previous depression diagnosis, with at least one episode occurring during the child's lifetime and ii) do not have a current or previous psychiatric diagnosis themselves, will be assigned to one of two conditions: an interpretation bias intervention (n = 50) or a structurally similar placebo intervention (n = 50). The interpretation bias intervention consists of a short lab-based cognitive reappraisal of interpretations training, a four-week app-based Cognitive Bias Modification of Interpretations intervention and interpretation bias specific if-then plans. Interpretation bias will be assessed before and after the intervention using the Scrambled Sentences Task. The effect of the intervention on participants' stress response will be assessed by salivary cortisol collected at five different time points: from immediately before until 45 min after administering the Trier Social Stressor Test for Children. Stress reactivity will be measured via baseline to peak cortisol and stress recovery will be measured via the 45 min cortisol marker. We hypothesise that children who participate in the interpretation bias intervention will display a positive shift in interpretation bias and this, in turn, will alter their stress response. Children who receive the placebo intervention are expected to show a smaller positive shift in interpretation bias and stress reactivity. DISCUSSION: The findings of the present study will contribute to models of familial depression transmission as well as informing preventive interventions. If training a more positive interpretation bias subsequently alters participants' stress response, then incorporating such tools may increase the efficacy of existing preventive interventions. TRIAL REGISTRATION: Deutsches Register Klinischer Studien DRKS00028842. Registered August 19, 2022.

The influence of outcome expectancy on interpretation bias training in social anxiety: an experimental pilot study.

BACKGROUND: Cognitive bias modification for interpretation (CBM-I) trainings have shown positive effects on interpretation bias in both active interpretation bias training conditions and structurally similar control conditions. Outcome expectations have been suggested to contribute to these placebo effects. The goal of this pilot experimental study was to test the feasibility of positive expectancy induction, to gain preliminary insight into whether this has implications for the efficacy of CBM-I training, and to assess the feasibility of recruitment and the overall study design. METHODS: Socially anxious individuals aged 18 years and older received a single session (approx. 45 min) of either CBM-I or placebo training preceded by either a positive expectancy induction or no expectancy induction. We first tested whether the expectancy induction had modified participants' expectations of training. We then explored the effects of CBM-I training and expectancy induction on interpretation bias. Finally, we assessed the feasibility of recruitment and further study procedures. RESULTS: Due to pandemic-related difficulties, fewer participants were recruited than initially planned. Thirty-four (22 females and 12 males) participants were randomly assigned to one of four conditions (interpretation bias training + high expectancy = 10, interpretation bias training + no expectancy = 8, placebo training + high expectancy = 11, placebo training + no expectancy = 5). Participants in the positive expectancy condition had more positive expectations of the training (CBM-I or placebo) than participants in the no expectancy condition. We were unable to conduct the planned 2 × 2 × 2 analysis of interpretation bias due to the small sample size. When looking at these groups individually, we found that participants in the active training condition and participants in the high expectancy condition showed increases in positive interpretation bias and decreases in negative interpretation bias from pre- to post-training, while participants in the placebo and no expectancy conditions showed no change. CONCLUSIONS: These findings suggest that the expectancy manipulation utilized in this study may be adopted by future studies which investigate outcome expectations as an unspecific mechanism of CBM-I. Preliminary analyses suggest that participants' expectations are likely to play a role in the effect of CBM-I training, although these effects require replication in a larger sample. Several observations about the study feasibility were made which could inform future trials. TRIAL REGISTRATION: Retrospectively registered on the August 23, 2022, through the German Clinical Trials Register ( DRKS00029768 ).

Neural prediction errors depend on how an expectation was formed.

When a visual event is unexpected, because it violates a train of repeated events, it excites a greater positive electrical potential at sensors positioned above occipital-parietal human brain regions (the P300). Such events can also seem to have an increased duration relative to repeated (implicitly expected) events. However, recent behavioural evidence suggests that when events are unexpected because they violate a declared prediction-a guess-there is an opposite impact on duration perception. The neural consequences of incorrect declared predictions have not been examined. We replicated the finding whereby repetition violating events elicit a larger P300 response. However, we found that events that violated a declared prediction entrained an opposite pattern of response-a smaller P300. These data suggest that the neural consequences of a violated prediction are not uniform but depend on how the prediction was formed.